I've heard of many studies saying that depression and suicide are most prevalent around the winter holidays. The impression I'd gotten was that this is because of the holidays: people are depressed that their Christmas isn't as good as they'd like it to be, or something of that nature.

But a few days ago it dawned on me that that's likely not the case at all. Other studies demonstrate that people tend to get depressed when days are dark and short. Yule, the shortest day of the year, is right around the corner, and it is winter, even here in sunny California ;)

So, perhaps its not that the holidays cause depression in some people, but rather that they are when they are because they help alleviate depression for many more people.